ISSN:0899-0042    

DOI:10.1002/chir.530010202

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

ISSN:0899-0042    

DOI:10.1002/chir.530010203

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractMany drugs contain a chiral centre, or such a centre is introduced during metabolism of the drug in man and in animals. If a single chiral centre is present, the drug will normally exist as a mixture of two enantiomers, of which one may have quite different pharmacologic and/or toxic effects than the other. Chiral drugs that are used in psychiatry, and some other pharmacologically related drugs are identified, and the implications of the presence of one or two chiral centres in these drugs are discussed. Differences in pharmacologic properties of drug and metabolite enantiomers are identified and discussed. Also reviewed are the properties of some drugs used in psychiatry that both are chiral and display geometric isomerism.

ISSN:0899-0042    

DOI:10.1002/chir.530010204

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractLittle is known about the stereochemistry of sulfation of chiral phenolic drugs. In this study we examined several in vitro approaches to this question, using (+)‐, (−)‐, or (±)‐terbutaline as the substrate and the rat liver cytosol as the phenolsulfotransferase enzyme source. The cosubstrate PAPS was either generated by the cytosol from inorganic sulfate and ATP or added to the cytosol. The intact sulfate conjugates formed were determined by HPLC. Using the PAPS generating system, which is best suited for the production of relatively large quantities of sulfate conjugates, with the individual enantiomers as substrates, (+)‐terbutaline was conjugated to a much greater extent than (−)‐terbutaline; the (+)/(−)‐enantiomer ratio was 7.3 ± 0.3 (mean ± SE). When (±)‐terbutaline was the substrate and chiral derivatization was employed to separate the sulfate enantiomers formed, a similar (+)/(−)‐enantiomer ratio of 7.9 ± 0.2 was obtained. With PAP35S added to the cytosol, an approach best suited for kinetic studies, the substrate concentration dependence of sulfation could be determined. TheKm appfor this reaction was identical for (+)‐ and (−)‐terbutaline. However, theVmax appwas 8.1 ± 0.4 times greater for (+)‐terbutaline. This study for the first time shows enantioselectivity in sulfation of a chiral phenolic drug. The experimental approaches used should be valuable for human studies of stereoselectiven sulfation

ISSN:0899-0042    

DOI:10.1002/chir.530010205

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe enantioselectivity of the in vitro conversion of simple prochiral and chiral aliphatic alkenes into oxiranes by liver microsomes of untreated or induced (phenobarbital) rats, of untreated or induced (phenobarbital, benzo[α] pyrene) mice, and of humans was determined by complexation gas chromatography. The enantiomeric excess (ee) of the epoxides extends from 0 (trimethyloxirane) to 50% (ethyloxirane). The configuration (R or S) of the enantiomers formed in excess is consistent for homologous oxiranes but is species dependent and in some cases influenced by enzyme induction. Enantioselectivity differences of aliphatic alkene epoxidation by human liver microsomes of four individuals are negligible

ISSN:0899-0042    

DOI:10.1002/chir.530010206

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractOptical enrichment from racemic dansyl‐leucine, dansyl‐norleucine, and dansyl‐phenylalanine with both β‐ and γ‐cyclodextrins in water is reported. Initial crystallization yielded the dansyl‐L‐leucine isomer complexed in excess with β‐cyclodextrin with an optical purity of 62–78% depending on experimental conditions. The optical purities obtained forL‐norleucine andL‐phenylalanine were 71 and 64%, respectively. The optical purity can be increased with continued recrystallization. The dansyl‐D‐leucine isomer was obtained in the mother liquor with an optical purity of 54–93% depending on experimental conditions. The optical purities obtained forD‐norleucine andD‐phenylalanine were 72 and 58%. The optical purity of the isomer depended on the molar ratio of host:guest and the pH value of the solution. Optimum enrichment of both enantiomers was achieved with host:guest ratios of 2 : 1 and 3 : 1. Although maximum crystalline yield of the dansyl‐leucine/CD inclusion complex was obtained at a pH of 3.5, optical purity of both enantiomers was less than that obtained at other pHs. The influence of the molar ratio of host:guest and the pH value of the solution are discussed. This method is suitable for

ISSN:0899-0042    

DOI:10.1002/chir.530010207

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThe direct enantiomeric resolution of albendazole sulfoxide (SOABZ), an anthelmintic drug belonging to the benzimidazole class, is reported on a chiral stationary phase (CSP) synthesized by covalent binding of (S)‐N‐(3,5‐dinitrobenzoyl)tyrosine‐O‐(2‐propen‐1‐yl) methyl ester on a γ‐mercaptopropylsilanized silica gel. A comparison with the resolution achieved on commercially available Pirkle‐type CSPs obtained fromN‐(3,5‐dinitrobenzoyl) derivatives of (R)‐phenyglycine or (S)‐phenylalanine is described. Some structurally related chiral sulfoxides including oxfendazole (SOFBZ) are also studied. Optimization of the mobile phase nature and composition is investigated showing that a hexane–dioxane–ethanol ternary mixture affords an almost baseline resolution (Rs= 1.25); however, in this case, albendazole sulfone (SO2ABZ) is eluted between the two sulfoxide enantiomers; accordingly, a hexane–ethanol mobile phase would be preferred for biological samples containing both metabolites. The influence of temperature on the resolution is depicted with a hexane–ethanol mobile phase. Finally, application to the enantiomeric assays of SOABZ in plasmatic extracts of rat, sheep, bovin, and man after oral administration of albendazole (sulfoxidized to SOABZ and SO2ABZ) is reported. Some distortions in the enantiomeric ratios ar

ISSN:0899-0042    

DOI:10.1002/chir.530010208

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractOptical resolution on the analytical scale of a number of racemic pharmaceuticals and some other biologically active compounds has been studied using immobilized bovine serum albumin (BSA) as the stationary phase. For some of the compounds the elution order was determined by the use of optically enriched fractions obtained from a preceding passage of a sample through a preparative column containing microcrystalline triacetylcellulose (MCTA). The reversal in the sign of optical rotation shown in the polarimetric elution profile from the latter, combined with the integrated peak area ratio obtained on resolution on the analytical column, gave directly the order of elution. For one of the benzothiadiazines studied (bendroflumethiazide), increasing the pH of the mobile phase produced opposite effects on the retention of the two enantiomers, leading to a large effect on the separation factor. For many of the compounds studied, high separation factors (α>2) could be achieved

ISSN:0899-0042    

DOI:10.1002/chir.530010209

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractThree chiral stationary phases, obtained by derivatizing γ‐mercaptopropylsilanized silica gel with quinine, quinidine, and cinchonidine, have been employed in the resolution ofN‐acyl derivatives of β‐hydroxyphenethylamines. The use of circular dichroism for detection and NMR analysis of analyte–selector mixtures provides an experimental basis for preliminary assignment of a recognition

ISSN:0899-0042    

DOI:10.1002/chir.530010210

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY

摘要:

AbstractHands can be used to demonstrate the three‐point model of chiral recognition. The points of attachment are thumb, forefinger, and middle finger. This vivid model has the advantages of simplicity, perspicuity, and availability at any time, although two persons are necessary. It can be shown that two interactions are not sufficient for chiral recognition but that three attractive or two attractive and one repulsive attraction are needed. It can also be used to explain some possibilities of weakening or elusion of the three‐point mo

ISSN:0899-0042    

DOI:10.1002/chir.530010211

出版商:Alan R. Liss, Inc.    

年代:1989

数据来源: WILEY